Power-hammer.



C. JACKSON. POWER HAMMER. APPLICATION FILED MAY 31. 1904.

Patented Mar. 15, 1910.

UNITED STATES PATENT CORWILL JACKSON, OF D ENVER, COLORADO, ASSIGNOR T0 NORTHERN ELEGT'PAB MANUFACTURING COMPANY, OF MADISON, WISCONSIN.

POWER-HAMMER.

speciicatioii of Letters Patent.

Patented Mar. 15,

Application filed May 131, `1.9M. i Serial No. men.

4To all whom 'it may concern:

Be itlknown that l, Conwiim JACKSON, a

' citizen of the United -States, residing in the cityand county of Denver and State of Colorado, have invented certain new and useful improvements in lou'er-l-laniniers; and l'` do declare the following` to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had tothe accompanying drawings, and to the letters andtigures of reference marked thereon, which form a part of this specification.

My invention relates to improvements in power hammers.

My iiyiprovement consists of a tool loosely mounted and arranged to be acted on by a hammer mounted on the armature of an electric motor and rotating therewith. .This hammer is pivotally connected with a disk mounted on the armature shaft and is adapt-f 'ed to swing outwardly in response to the centrifugal force incident to the rotation 0f,

the disk. rllhe disk is cut away adjacent the hammer ony one side, to allow the hammer to fold iito the said recess while it is )assing the extremity ot the tool upon wliich it acts. The motor is mounted in a casing of suitable size to allow the hauiiiiei' to swing outwardly under the influence of centrifugal force, as loon as it has passed the extremity of the tool. Provision is made for closing the circuit through the motor and starting the latter automatically7 as the cutting extremity of thevtool is applied to the surface to be acted on and given suitable pressure' whereby two contacts are brought together, through which the circuit is closed. This device is adapted for use in all the varied relations where an article of its class is ordinarily employed.

Having briefly outlined my improved construction as well as the function it is intended to perfornnl will proceed to describe the/ saine in detail reference being made to the accompanying drawing in which -is illustrated an embodiment thereof.

ln this drawing, Figure 1 is a top View of my improved hammer with the upper part of the casing inclosing the motor, removed and the shell connected withA the motor easing shown 'in section. Fig. 2 -is a sectional elevation, the section being taken at right lextremity thereof, lare both angles to that shown in Fig. l. Figs. Santi.

4 are sections taken on the lines BMS and 4-4 respectively of Fig. 1.

The same reference characters indicate the saine parts in all the views.

Let A designate the body of the motor casing and A a detachable-hoiising con nected with the casing by means of stud bolts A2. The .body of the casing A is provided with a threaded rejection A, upon which is screwed a c" liiidrical casing whose outer extremity is rovided with a plug A5 which is screwed into the forward end ofthe cylindrical casin or that remote from the motor casing. Tris plug is provided with a milledl zone A exposed for convenience `in turning the latter for the purpose of insertion and removal. The ping A at the forward extremity of the cylinder and the projection A? which enters the rear rovided with central openings through which the tool B passes. This tool is sui-rounded by a bushu ing B and is loose' therein. The forward extremity of thef'i'bushiug bears against a shoulder B2 formed on the shank of the tool. ln the rear of this shoulder a collar B3 is secured to the bushing, and inthe rear of the collar an insulating block l is loosely mounted on the bushing, while in the rear the block C is a second insulating block l), the latter being secured to the cylinder by screws D. The two blocks C and l) are interiorly recessed or chambered to receive a.

coil spring' E whose extremities bear against to which lead electrical conductors G and ll,

4These conductors both Jpass `through .openings A" `formed in thepiojection A3 of the motor housing. The conductor passes through the housing to one pole of the electrical source (not shown); while Jthe con doctor Gr passes to one of the field coils l2 of the motor, thence through one of the brusl'ics l to theV armature, thence to the brush l? and thence by way of a conduct/or G to the other field 'coil I, and thence through a con- Cnis attached( lili? diietor G2 to the other pole of the electrical 'I source. The bushing 'BC is surrounded by collar B* which is made fast thereto. collar is located in therear of the .insulating sure ceases to act on block D, and between the collar B* andthe projection A3 of the motor housing, is interposed a coil spring J which is under sulficient tension to hold the bushing normally in engagement with the shoulder B2 of the tool. The contacts D2 are normally separated from the contact ring C, through the instrumentality of the coil spring E which is under suflicient tension to force the block C, the bushing B and the tool B forwardly to eifect the separation of the said contacts and break the circuit, except when the cutting extremity of the tool is pressed with suilicient force against some object., to cause the insulating block C to move rearwardly far enough to bring the contact ring C into engagement with the contacts D2; and when the tool is in operation, the pressure of the cutting extremity of the tool against its work is sufficient for the said purpose. The parts are then in the position shown in Fig. 2.' When the circuit is closed the insulating block C is locked in the circuit closing position by a pin K, fastened on a spring K,

made fast to the cylinder, as shown at K2. The collar B3 of the bushing B is beveled. The projection K3, attached to the spring K, passes through a slot A8 formed in the cylindrical casing. As soon as the presthe cutting extremity of the tool, the spring J will force the bushing B forwardly and bring the collar B3 into engagement with the projection K, whereby the spring K is forced outwardly suthcientlyto release the pin K from the circumferential recess C2 formed' in the insulating block C. The recoil of the spring lil,- then acts to force the insulating block C to the position shown in Fig. l, breaking the circuit and quickly separating the contact ring C from the contacts D.

The rear extremity of the tool B enters the chamber of the motor housing A., and is in position to be acted on by the hammer L vwhich is pivoted at L to a disk M made fast to the armature shaft N and reinforced :1t M opposite the hammer L, whereby the disk is balanced. The disk is cut out as. shown at M2, to allow the hammer to fold thereinto as shown by dotted lines in Fig. 2, after the hammer strikes the rear Aextremity oif the tool. AAs the hannneroccupies the same plane as the body of the disk, this recess is necessary in order to allow the hammer to pass the rear extremity of the tool. As soon as this occurs, however, the centrifugal force will throw the hammer outwardlywhereby it will assume its limit of outward movement or that indicated in Fig. 2.

From the foregoing description the use and operation'of my improved hammer will be readily understood. Assuming that the parts are in the pbsition shown in Fig. l, as the user begins the operation of the tool, he

parts in the circuit-closing position. *The rotation of the motor armature, together with the disk M and the hammer L, then commences; and every time the hammer L makes a revolution, it strikes'the rear extremity of the tool, and as often as it strikes this tool, it folds into the recess M2 while passing the tool after which it returns toits' outward position whereby it is made toact mosti effectively upon the tool.

The spring J tends to maintain the tool-in: its extreme outer position in which position its blow-receiving end is clear of the hammer. Therefore, by moving the drill so as to bring the tool against the work and then moving the drill into various positions relative to the work, the tool is forced` inward against the'tens1on of the spring-so yas'to bring its blow-receiving end `into 4different operative relations to the hammer. ,This is o importance in that the force of the blows on the drill may be varied so as to cause it'V v to operate most advantageously irrespective of the character of the material operated upon. y

Having thus .described my invention,

what I claim is:

1. The combination with an electric motor, a hammer operated by the motor, a casing, a tool inovably mounted in the casing, a bushing also mounted in the casing and through which the tool passes, the latter being loose in the bushing, the tool having a shoulder which the forward extremity ofV the bushing engages, the bushing being provided witha collar, a coil spring interposed between the casing and the said collar, another collar mounted on the bushing forward of the lirst named collar, an'insulating block movably mounted in the casing and adapted to engage the forward collar of the bushing, another insulating block fast in the casing inthe rear of the first named block, the adjacent faces of the two insulating blocks being provided with contacts located in the circuit of the field coils of the motor, a coil spring interposed between the two insulating blocks and having a tendency to force the movable block forwardly to break the circuit, means for locking the movable insulating block inl the casing comprising a spring-actuated pin having a forwardly located, interiorl projectin part, lying in the path of the orward col ar of the bushing when the latter is driven 'to its forward `limit'of movement lwhereby the interiorly projecting part is acted on to disengage the spring-actiiated pin from the insulating block thus releasing the latter.

2.In a. tool of the class described, the combination with an electric motor and a easing, of a bushing movable longitudinally in said casing, a-spring whose tendency is to force the bushing to its forward limit oi" movement, circuit-closing contacts located in the casing, means for lockingthe movable contact in the circuit-closing position, the said locking means` having` a part projecting into the casing, the bushing having u collar adapted to engage the said projection of the locking device and release the movable Contact when the bushing is driven foi'-,

wardly,y a` spring acting to move the nnlocked contact suiiciently tobreak the circuit.7 and a tool passing through the bushing and provided with a shoulder acted on by the bushing'.

3. The combination with an electric motor comprising a casing forming a part oi the magnetic circuit of said motor and an armatnre inclosed by and jonrnaled in Said casing, said casing being` formed with a toolreceiving passage or opening, a centrifugal herinner located in said casing and rotated by said armature, of a shell secured to said casing, e tooisnpported in enid sheli with one end projecting through said opening or passage into the easing in a position to be struck by Said hammer7 a pair of relativeiy movable contacts in said shellv the engagement of said contacts being controlled by the position of the tool, and a lead extend ing from one of said contacts to the motor?. said lead being located within said casing' and said shell.

In testimony whereof I atiix my signature in presence of two witnesses.

CORVVILL JACKSON.

Witnesses i DnNA NELSON, 

